package com.fly.servlet;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class IdentifyServlet extends HttpServlet{
	public static final char[] CHAR = {'2','3','4','5','6','7','8','9','A','B','C','D','E','F','G','H','J','K','L','M','N','P','Q','R','S','T','U','V','W','X','Y','Z'};
	public static Random random = new Random();
	public static String getRandomString(){
		StringBuffer buffer = new StringBuffer();
		for(int i = 0;i<6;i++){
			buffer.append(CHAR[random.nextInt(CHAR.length)]);
		}
		return buffer.toString();
	}
	public static Color getRandomColor(){
		return new Color(random.nextInt(255),random.nextInt(255),random.nextInt(255));
	}
	public static Color getReserveColor(Color c){
		return new Color(255-c.getRed(),255-c.getGreen(),255-c.getBlue());
	}
	public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException{
		response.setContentType("image/jepg");
		String randomString = getRandomString();
		request.getSession(true).setAttribute("randomString", randomString);
		int width = 100;
		int height = 30;
		Color color = getRandomColor();
		Color reserve = getReserveColor(color);
		BufferedImage bImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);
		Graphics2D g = bImage.createGraphics();
		g.setFont(new Font(Font.SANS_SERIF,Font.BOLD,16));
		g.setColor(color);
		g.fillRect(0, 0, width, height);
		g.setColor(reserve);
		g.drawString(randomString, 18, 20);
		for(int i = 0,n = random.nextInt(100);i<n;i++){
			g.drawRect(random.nextInt(width), random.nextInt(height), 1, 1);
		}
		ServletOutputStream out = response.getOutputStream();
		JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
		encoder.encode(bImage);
		out.flush();
	}
}
